Surface activated bonding for Sn-Ag and their oxidation mechanism

Sn-based alloys are expected to be widely used in upcoming lead-free electronic packaging field for environment reason. In this approach, we introduced a room temperature bonding for Sn-Ag with the Surface Activated Bonding (SAB) method to eliminate the high temperature induced problems in the Sn-Ag conventional bonding process. Fundamental oxidation process of Sn-Ag associated with the bonding strength of flat (rms = 5.5 nm) and non-flat samples (rms ∼ μm) was investigated. XPS results showed that the oxidation sensitivity of flat samples was higher than that of non-flat samples. Significant dependence of surface roughness on the tensile strength was observed.